Paper and pulp mills generate large volumes of wastewater containing lignin-derived compounds that are challenging to degrade using conventional wastewater treatment methods. This study presents a novel biofilm-based process for enhanced lignin removal in wastewater using the fungus Neurospora discreta, which is capable of degrading lignin effectively and forming strong biofilms on the air-liquid interface under specific conditions. The process was optimised using the Taguchi statistical design of experiments approach, evaluating three factors - pH, copper sulphate, and trace elements, at three levels. The experimental data was analysed against three responses: lignin degradation efficiency, and the activities of two ligninolytic enzymes, polyphenol oxidase, and versatile peroxidase. Results indicated that wastewater pH was the most significant parameter affecting lignin degradation efficiency and enzyme activities. Over 70% lignin degradation was achieved at pH 5 and 6 with copper sulphate concentrations above 4 mg L-1, while the degradation efficiency dropped drastically to as low as 45% at pH 7. Reversed-phase High-Performance Liquid Chromatography analysis demonstrated the effects of the three factors on the polar and non-polar components of lignin in the wastewater, revealing a clear decrease in all peak areas after treatment. Additionally, the relationships between biofilm properties including porosity, water retention value, polysaccharide and protein content, and lignin removal efficiency were demonstrated. This study also reports for the first time, the presence of versatile peroxidase, a ligninolytic enzyme, in Neurospora spp.